Early on Thanksgiving morning near Beaumont, Texas, dense thick fog covered the highways, resulting in a massive and deadly multi-vehicle accident. Roughly a hundred vehicles were involved, many of them 18 -wheelers, leaving two people dead, and injury estimates involving up to 120 people taken from the scene and treated. The vehicles involved included tractor-trailer trucks, minivans, pickups, package carriers and cars.
Unfortunately, fog is the cause of many multi-vehicle crashes each and every year. The diffusion of light caused by the suspension of the very small moisture droplets in the air can distort the drivers perception, greatly limiting visibility, reducing visual contrast and creating visual confusion amid the dense undistinguishable white background.
Because our perceptions of speed are relative to other objects, when those objects disappear from view, our perceptions of speed can change, tricking the mind into believing that a vehicle in front of us, for example, is traveling faster or slower than it actually is. This can even result in mistaking a stationary object as a moving one.
Additionally, fog can affect your perceptions of distance. Our brains generally recognize sharp dark clear objects as near and light slightly blurred objects as farther away. Fog changes the normal data our brains evaluate and react to.
Here a few suggestions when encountering fog while driving.
- Do NOT turn on your bright lights as the additional diffusion of light particles will increase the visibility problems. Use your fog lights as yellow lights reflect less light than your normal headlight beams.
- Adjust your speed for conditions – pull over if a safe spot is available and wait it out if necessary. Not driving in fog is the best suggestion of all. Often this is a difficult decision as the density of fog changes, causing you to believe it is drivable one minute while suddenly becoming treacherous the next. Fog conditions usually subside within a reasonable period of time, so waiting it out and arriving late is often the better option.
- If you find yourself unable to pull off the road safely, allow a much larger space between yourself and surrounding cars to allow for delays in judgment and room for breaking. Usually allowing the maximum space while still making slight visual contact provides both a degree of safety and a perspective of relativity that can help you navigate through to the safest place to exit.